Electrochemical Deposition and Dissolution of Aluminum in NaAlCl4 Melts: Influence of and Sulfide Addition

Effects of the additives , sulfide, and their combined influence on aluminum deposition and dissolution in saturated with have been studied by polarization measurements, galvanostatic deposition, and current reversal chronopotentiometry (CRC). The solubility of was found to be in the melt at 175°C. Aluminum‐manganese alloys can be deposited in saturated with both and , resulting in a slight increase in cathodic overpotentials. The codeposition of the binary alloys at current densities below 4 mA/cm2 gave rise to formation of deposits so compact that their specific average volumes are of the theoretical value. The content of manganese in the alloy deposits was found to be between 8–11 a/o. It was found that the manganese content in the deposits did not depend on the current efficiency. The presence of sulfide in results in the formation of more spongy deposits at low current densities, and thus destroys the beneficial effects of when both additives are present, but prevents formation of dendritic deposits at high current densities. Coulombic ratios of dissolution to deposition were found by CRC measurements to be affected by the nature of the substrate.